Blanking die means with resiliently supported stripper plate means



March 28, 1961 s WENNES 2,976,754

BLANKING DIE MEANS WITH RESILIENTLY SUPPORTED STRIPPER PLATE MEANS FiledApril 21, 1958 i IIVI/ENTOR 5 BY SEW/EN B. WEN/V55 BLANKING DE MEANSWITH RESILIENTLY SUPPORTED STRIPPER PLATE MEANS Stephen B. Wennes,Minneapolis, Minn, assignor to Dayton Rogers Manufacturing C0,,Minneapolis, Minn, a corporation of Minnesota Filed Apr. 21, 1958, Ser.No. 729,842

1 Claim. (Cl. 83-139) This invention relates to the method of andapparatus for producing apertured metal stampings and the like.

In the past it has been necessary, in the production of apertured metalstampings, to produce the part from the sheet metal by the use of ablanking die and blanking punch, and when the part has been produced inthis manner, the part has been inserted into another piercing punch anddie assembly to pierce one or more apertures in the part. Obviously,this has required the use of two difierent punch press machines andbecause the successive steps were necessary, labor costs in handling theparts materially increased the cost of production.

An object of my invention is the provision of a new and improved methodfor easily and inexpensively producing apertured parts of sheet metaland the like in a single operation.

Another object of my invention is the provision-of an improved compoundblanking and piercing apparatus of simple and inexpensive constructionand operation for producing sheet metal parts.

Still another object of my invention is the provision of a novelapparatus for simultaneously blanking a part from sheet metal stock andthe like and piercing one or more apertures in the part produced.

A further object of my invention is the provision of a new and novelmethod of producing from sheet metal or the like, a part having anaperture within the periphery thereof by simultaneously punching throughthe sheet metal stock in one direction to blank the part out of thesheet metal stock and simultaneously punching through the part in theother direction to pierce an aperture in the part, and then strippingthe sheet stock ofi the blanking punch and stripping the part off thepiercing punch.

These and other objects and advantages of my invention will more fullyappear from the following description made in connection with theaccompanying drawings wherein like reference characters refer to thesame or similar parts throughout the several views and in which:

Fig. 1 is a detail elevation view, with certain parts shown in section,of the punch and die assembly embodying the present invention, andshowing the assembly in operative condition prior to the starting of anoperating cycle;

Fig. 2 is a detail elevation view, with certain parts shown in section,and showing the assembly in an intermediate stage of its operatingcycle, substantially at the moment blanking and piercing of the materialbegins;

Fig. 3 is also a detail vertical section view with certain of the partsshown in section and showing the assembly in an intermediate stage ofthe operation cycle, substantially at the moment blanking and piercingof the part has been completed;

Fig. 4 is also a detail elevation view with certain of the parts shownin section and showing the assembly in an intermediate stage of theoperational cycle substantially at the moment of completion of strippingof the blanked part and stock from the punches and die; and

Fig. 5 is also a detail elevation view with certain of the parts shownin section and showing the assembly substantially at the final stage ofits operational cycle wherein the parts and slugs have been removed andthe .stock is ready to be moved for starting another operational cycle.

The method employed herein and comprising a portion of the presentinvention will be apparent from the description of the construction andoperation of the compound blanking and piercing assembly which isindicated in general by numeral 10.

The assembly 10 is adapted to be mounted in a conventional punch pressmachine, and in the drawings the vertically reciprocable ram 11 and thebolster plate 12 which is rigid with the bed of the machine are shown.Because the means by which various parts are secured to the ram andbolster plate of the punch press machine are well known to personsskilled in the art, many of these details are eliminated in order toemphasize the primary aspects of the present invention.

The assembly 10 includes a blanking die 13 having a die opening 14formed therein and shaped to the configuration of the part to be blankedfrom the sheet stock S such as sheet metal or the like. It will be notedthat the die 13 faces downwardly and the cutting edge of the die 13 isdisposed at the lower surface thereof. A downwardly facing piercingpunch 15 is disposed within the blanking die opening 14 at apredetermined position corresponding to the position of an aperturewhich is to be produced in the part which is to be blanked.

Means are provided for mounting the blanking die 13 and the piercingpunch 15 on the ram of the machine. The piercing punch 15has its uppermounting end portion 16 secured in a suitable aperture in a punch holderplate 17. The die 13, which underlies the punch holder plate 17 issecured in predetermined relation with the punch holder plate and isafiixed, along with the punch holder plate 17 to a back-up plate 18 bysuitable means (not shown). The back-up plate 18 is afiixed to a spacerplate 19 which is affixed to the ram 11 of the machine.

The die 13 and punch holder plate 17 have alignment pin-receivingopenings 20 therein.

Means are provided in the die opening 14 and around the piercing punch15 for stripping the part out of the die opening and in a downwarddirection, and in the form shown, such means comprise a body 2-1 ofresiliently compressible and expandable material, which in the formshown is constructed of rubber, but could of course be other suitableresiliently yieldable material. The body 21 is shaped to conform to theconfiguration of the die opening 14 with provision made to allow thepiercing punch 15 to extend therethrough. It will be noted that thelower face and cutting edge of the piercing punch 15 is disposed in thesame horizontal plane with the cutting edge of the die 13. The bottomface of the body 21 engages the part as it is being blanked and permitsmovement of the part upwardly into the die opening. The bodysubsequently ejects the part after the same is blanked.

The blanking assembly 10 also includes a blanking punch 22 below the die13 and in alignment with the die opening 14- thereof. The punch 22 has aperipheral configuration substantially identical to that of thedieopening 14. Blanking punch 22 also has a die opening and in the formshown, such means include a stripper plate 24 which is constructed ofsomewhat thinner stock than the punch 22, and is fabricated to fitaround the punch 22 for vertical movement with respect tothe punch.

The bolster plate 12 and the bottom holder 25, which is suitably affixedto the bolster plate, provide the means for supporting the punch 22during a blanking operation.

Means are provided for mounting the blanking punch 22 in such a positionthat it is normally spaced upwardly from the bottom holder 25 and topermit, during a blanking operation, downward movement of the punch intosupported relation with the bottom holder 25 and to permit additionaldownward movement of the stripper plate 24 as the punch 22 moves intothe die opening 14. In the form shown, such means include a pneumaticdie cushion 26 which is suspended from the bolster plate 12 in aconventional fashion and which is constructed so that the upper portion27 of the cushion and the pin pad 28 are movable downwardly with respectto the bolster plate 12 when substantial downward force is exertedagainst the pin pad 28. The construction and operation of pneumatic diecushions is well known to persons skilled in the art, and it shouldmerely be noted that the die cushion 26 has resiliently yieldingproperties. When downward force is applied thereto, the pin pad 28 isresiliently urged in an upward direction so as to oppose the force andcause upward movement of the pad when the force is released. A pluralityof upright punch and stripper plate-mounting pins 29 extend throughsuitably provided apertures 30 in the bolster plate i2 and bottom holder25 and are slidable therein for limiting vertical reciprocation. Pins 29have reduced upper end portions 31 defining shoulder surfaces 32. Thereduced upper end portions 31 of the pins project through bearingapertures 33' in the punch holder plate 34. The reduced upper endportions 31 of the pins 29 are slidable in the apertures 33. It will benoted that the punch holder plate 34 has a slug or material-dischargingopening 35 extending vertically therethrough in alignment with thedownwardly enlarged piercing punch-receiving opening 23 in punch 22. Itwill be understood that the punch 22 is afiixed to the punch holderplate 34 by any suitable means.

The stripper plate 24 overlies the upper end surfaces 36 of the pins 29and it will be seen that the stripper plate 24 is normally spaced abovethe punch holder plate 34 to permit limited vertical movement of thestripper plate 2t4i with respect to the punch holder plate 34 and punch22.

Stop means are provided for limiting the upward movement of the punchholder plate 34- and the pins 29 and therefore upward movement of thestripper plate 24. In the form shown, such means comprise limit blocks37 which have shoulder surfaces 33 facing downwardly to bear against theupper surface of punch holder plate 34 and thereby limiting upwardmovement of the punch and pins 29, and stripper plate 24.

Alignment pins 39 are atfixed to the punch holder plate 34 and projectthrough suitable apertures in the stripper plate 24 for projection intothe apertures 20 of the die 13 and punch holder plate 17.

Means are also provided for sweeping the slugs from between the punchholder plate 34 and the bottom holder 25 when the slugs have beenejected downwardly through the openings 23 and 35 in the punch 22 andplate 34 respectively. In the form shown such means comprise air nozzles40 which direct a stream of air beneath the punch holder plate 34 andthe bottom holder 25 to sweep the slugs off the bottom holder 25. Airnozzles 41 are also provided above the stock S and below the die 13 whenthe same is in its upper position so as to direct a stream of air forejecting the part P out of the die assembly.

In operation, the stock S is positioned in overlying relation to thestripper plate 24 and to the punch 22. Subsequently the ram 11 isoperated to move the die 13 and punch 15. downwardly to the dottedposition F shown 7 withdrawn from the die opening.

in Fig. 1 so as to clamp the stock between the blanking punch 22 andblanking die 13 and between the piercing punch 15 and the portions ofpunch 22- bounding the periphery of die opening 23. As best seen in Fig.2, the ram 11 continues to move downwardly, and as this occurs, thepunch 22 is also driven downwardly, along with the stripper plate 24until the punch holder plate 34 engages the bottom holder 25. Of course,as this happens, the bottom holder plate 34 moves downwardly away fromthe shoulder surface 38 of the limit blocks 37, and the sheet of stock Salso moves downwardly slightly.

As seen in Fig. 3, the ram 11 continues to move downwardly as the punch22 engages the bottom holder 25 and is stopped, and as the ram movesdown further, the compound blanking and piercing operation occurs andthe production of an apertured part P. The die 13 moves downwardly overthe punch 22 so as to cause the punch to project slightly into to dieopening 14. Simul taneously with this, the punch 15 moves downwardlyinto the die opening 23 to produce an aperture in the part P and toproduce the slug s which starts to fall downwardly through the openings23 and 35. Simultaneously with the movement of the punch 22 into the dieopening 14, the body 21 of resilient material is compressed to allow thepart P to move inwardly of the die opening, and at this same time, thedie 13 bears downwardly through the stock S on the stripper plate 24causing further downward movement of the pins 29 While the punch 22 andplate 34 remain stationary. It will be seen that when the actualpiercing and blanking has been completed the stock S surrounds the punch22. Subsequently the ram 11 starts to move upwardly to relieve thedownward force on the stripper plate and punch and of course the punchreleases the part I as the punch is The pneumatic die cushion 26 urgesthe pins 29 upwardly which first carries the stripper plate 24 and thenthe punch-holding plate 34 upwardly. The sheet of stock S is strippedoff the punch 22 and the punch and stripper plate return to their normalposition wherein further upward movement is restricted by limit blocks37. As the pressure of the punch on the part P is relieved, the body 21of resilient material in the die opening strips the part P downwardlyout of the die opening.

It will be seen that as a result of the upward movement of the punch 22and holder plate 34, the slug s which has dropped through the openings23 and 35 is "in the free and unobstructed space beneath the plate 34.

Air from the nozzles 44 and a l is then utilized to sweep the slug s andthe part P outwardly to one sidetof the assembly, substantially in themanner shown in Fig. 5.

It will be seen that I have provided a novel method of and apparatus forproducing an apertured part by simultaneously blanking the part fromsheet metal stock or the like and piercing the sheet metal within theperiphery of the part being produced. Although the description hereinhas been related only to the production of a single aperture in the partbeing blanked, it should be understood that a number of apertures may besimultaneously produced in the part during a single blanking andpiercing operation by employing a number of piercing punches in the dieopening and by forming a number of piercing punch-receiving dieopeningsin the blanking punch.

It will, of course, be understood that various changes may be made inthe form, detail, arrangement and proportion of the parts withoutdeparting from the scope of my invention which consists of the matterdescribed herein and set forth in the appended claim.

What is claimed is:

Apparatus for use in punch press machines and the like for producingapertured parts from sheet metal and the like, said apparatus comprisinga downwardly facing blanking die having a die opening, a downwardlyfacing piercing punch in the die opening, means mounting the blankingdie and piercing punch on the ram of the machine, stripper means in theblanking die opening and ejecting the blanked parts downwardly from thedie opening, an upwardly facing blanking punch below the blanking dieand in alignment therewith and having an upwardly facing piercingpunch-receiving die opening extending vertically therethrough inalignment with the piercing punch, a punch-holding plate underlying thepunch and secured thereto and having a material ejecting openingvertically therethrough and in alignment with the die opening in theblanking punch, a stripper plate surrounding the blanking punch at theupper cutting edge thereof, rigid blanking punch-supporting meansstationary with the bed of the machine, a plurality of upright punch andstripper plate-supporting pins slidably mounted in the punch-supportingmeans and having shoulder surfaces and upper end portions verticallyslidably mounting the punch-holding plate and also having means at theirupper ends supporting the stripper plate, and resiliently yieldablemeans supporting the pins with the shoulder surfaces and punch-holdingplate spaced above the punch-supporting means, the resiliently yieldablepin-supporting means continuously urging the pins upwardly, and stopmeans limiting upward movement of the stripper plate and pins, wherebythe punch and stripper plate, after having been driven downwardly by thedie, will be resiliently urged upwardly to strip the material from thepunch and to allow additional material to fall downwardly through thedie opening in the blanking punch and through the opening in thepunch-holding plate whereupon the material may be easily removed.

References Cited in the file of this patent UNITED STATES PATENTS828,226 Lorenz Aug. 7, 1906 928,256 Grissom July 20, 1909 2,200,886 KuhnMay 14, 1940 2,355,556 Peterson Aug. 8, 1944 2,371,565 Whistler Mar. 13,1945 2,417,414 Hornberger Mar. 18, 1947 2,494,018 Urquhart Jan. 10, 19502,576,295 Good Nov. 27, 1951 2,587,214 Polk Feb. 26, 1952

